Disapprove of university garment (4)
I believe the answer is:
tutu
'garment' is the definition.
(tutu is a kind of garment)
'disapprove of university' is the wordplay.
'disapprove of' becomes 'tut' (I can't justify this - if you can you should give a lot more credence to this answer).
'university' becomes 'u' (abbreviation for university).
'tut'+'u'='TUTU'
Can you help me to learn more?
(Other definitions for tutu that I've seen before include "Ballet dancer's costume" , "Female ballet costume" , "The old primate" , "outfit" , "A ballerina's short skirt" .)